1. Field of the Invention
The present invention relates to a polymer composite material in which a rigid polymer reinforces a flexible polymer at the molecular level and a method for preparing said composite material.
2. Prior Art
There have been developed polymer composite materials in which a reinforcing polymer having a certain rigidity is dispersed uniformly and microscopically in the matrix molecules so as to enhance mechanical properties of the polymer materials. However, said polymer composite materials were basically prepared by mixing the rigid polymer as a reinforcing material into the matrix polymer with solvent and therefore, the uniform mixture was difficult and the problems was occurred such as a decline of strength because the reinforcing material became rough and large.
To solve said problem, we provided a method for preparing a polymer composite material including a rigid polymer having a molecular diameter of 0.07 .mu.m or less dispersed microscopically at the molecular level in the flexible polymer matrix, in which monomer molecules to form a rigid polymer as a reinforcing material are polymerized in the flexible polymer matrix with no solvent in the molten and mixed state (Japanese Unexamined Patent Publication Tokkaihei No. 6-145534).
The compounding ratio of the rigid polymer is needed to be ncreased in the polymer composite material, in order to enhance the strength of the polymer composite material. However, if large quantities of the monomer forming the rigid polymer is added in the matrix at a time from the beginning, the rigid polymer agglomerates and becomes rough. And then, the molecular diameter exceeds the upper limit of the molecular diameter required to achieve the desired reinforcement effect, that is, a cross-sectional diameter of 0.07 .mu.m when cut at right angles to the longitudinal direction of the reinforcing material composed of said rigid polymer.
As disclosed in said published official gazette (Japanese Unexamined Patent Publication Tokkaihei No. 6-145534), in the case that the cross-sectional diameter of said rigid polymer exceeds 0.07 .mu.m, the strength of the polymer matrix material cannot be enhanced. And therefore, the strength of the polymer composite material could not be enhanced according to the method wherein large quantities of the monomer to form the rigid polymer is added in the matrix at a time from the beginning, even if the compounding ratio of the rigid polymer is increased.